Liquid cooling unit



A ril 12, 1949. c. BOLlNG ETAL 2,466,676

I LIQUID COOLING UNIT Filed April 19,- 1946 2 Shets-Sheet 1 a 2 M j/HI- Iant Y a. 2 0

L fl Z L April 12, 1949. e E

LIQUID COOLING UNIT 2 Sheets-Sheet 2 Filed April 19, 1946 INVENTOR IQLLATTORNEY Patented Apr. 12, 1949 LIQUID COOLING UNIT Cecil Boling, Brewster, and Alex J. Tigges, New York, N. Y.; said Tigges assignor to said Boling Application April 19, 1946, Serial No. 663,450

4 Claims.

Our invention relates broadly to refrigeration and more particularly to a cooling unit for a liquid cooler.

Among the objects of our invention is to provide a cooling unit which is compact in relation to its capacity.

Another object of our invention is to provide a cooling unit which is able to withstand a freezeup of the liquid without damage.

A further object of our invention is to provide a cooling unit which has a high rate of heat transfer between the liquid and the refrigerant.

In the illustrative embodiments of our invention the cooling unit is made up of at least one wiriwicoil 15 atleastcneliqiis coil, these coils being of siibstantiafly the same si ze'witli the turns of the refrigerant coil spaced between {and alternating with the turns of the liquid coil.

,'ium block. The aluminium casting not only provides excellent heat transfer from the liquid coil to the refrigerant coil, but in addition is made thick enough so that, in the event the contents of the liquid coil becomes frozen, it is able to withstand bursting pressure on the liquid coil resulting from the freeze-up. In order to prevent bursting of the liquid coil at the points where the ends thereof emerge from the casting, reenforcements are provided at these points. Preferably, such reenforcements are in the form of pipe fittings cast into the aluminium block and extend downwardly therefrom, which fittings also serve for connecting the ends of the liquid coil to the liquid pipes.

In accordance with one embodiment of our invention, in order to provide a unit having large cooling capacity in proportion to its size, we provide a pair of refrigerant coils connected in series, one of these coils being of smaller diameter than the other and disposed inside the other, Alterhating with the turns of these refrigerant coils greturgs ojlvp liquid coils which are connected in series.

We have also found that it is highly advantageous to assure against reverse work in a' liquid cooling unit of this type. By reverse work is meant the flow of heat from one turn of the liquid coil to another turn of the same coil in which the liquid is at a lower temperature. We have discovered that this may be avoided if the distance between any turn of a liquid coil and the closest turn of a refrigerant coil is less than the distance between the turn of the liquid coil and the closest adjacent turn of a liquid coil.

Further objects and advantages of our invention will be apparent from the following description considered in connection with the accompanying drawings which form part of this specification and of which:

Fig. 1 is a cross-sectional view of a liquid cooling unit in accordance with one embodiment of our invention;

Fig. 2 is a side view of the unit shown in Fig. 1, but with the casting shown in phantom;

Fig. 3 is a top View of the unit in accordance with another embodiment of our invention;

Fig. 4 is a side view of the unit shown in Fig. 3, but on a somewhat larger scale and with the casting in phantom; and

Fig. 5 is a cross-sectional view taken on the line 5-5 of Fig. 3 with the casting in phantom.

Referring more particularly to Figs. 1 and 2, reference character Ill designates an aluminum casting within which are embedded a pair of helical coils I2 and [4. Either of these coils may be the refrigerant ggihbut .it. .will beassumed that llifiili refrigeran i1 and t is the li quid coil.

The coil l2 msetter,etsafi'vaptitttr dfii'swt: able refrigerating system, or it may serve to congduct a liquid heat-t ren inediimi" The p and bottom turns of the coil l2 are provided with extensions [6 and 18, respectively, which extend axially to the upper and lower ends of the casting. Prior to the casting of the metal around the coils, these extensions are connected to fittings 20 and 22, respectively, the inner ends of which are cast within the metal.

In a similar manner the ends of coil I4 are provided with extensions 24 and 26 which extend axially to the end surface of the casting and are provided with fittings 28 and 30, the inner ends of which are cast into the metal.

If the liquid to be cooled is lead into the fitting 28 and the cooled liquid is withdrawn through fitting 30, the fitting 22 would normally constitute the refrigerant inlet and fitting 20 the refrigerant outlet in order to provide counterflow between the two fluids. Due to the alternating arrangement'of the turns of the refrigerant coil and the liquid coil, it will be clear that any turn of the liquid coil I4 is closer to an adjacent turn of the refrigerant coil l2 than it is to another turn of the liquid coil. This arrangement of the turns prevents reverse work, inasmuch as heat cannot flow from one turn of the liquid coil to a lower turn of the same coil in which the liquid is at a lower temperature, because heat attempting to flow in this manner would first reach arefrigerant turn and be absorbed thereby.

If the minimum thickness of the casting surrounding the coils is a quarter of an inch, it being assumed that the casting is made of aluminium and the outer diameter of the coils is one-half of an inch or less, we have found that the casting possesses sufficient strength to withstand the bursting pressure produced within the liquid coil in the event that the liquid freezes. Consequently, the unit will not be damaged by a freeze-up. Moreover, due to the fact that the fittings extend beyond the surfaces of the casting, they provide support against bursting where the pipes leave the casting. If the copper tubing of which the coils are formed emerged from the surface of the casting without any external support, it would be apt to burst at this point in the event of a freezeup. However, the fittings extend far enough beyond the surface so as to support the tubing for a distance far enough away from the casting so as to be beyond the point at which freezing will take place. Another advantage of having the fittings cast into the casting is that the ends of the coils are protected against being broken at these points by careless handling of the unit before it is installed in a cooler.

In the embodiment illustrated in Figs. 3 through 5, the casting is again represented by reference character l0, Reference character 32 designates an inner refrigerant coil which is connected at its lower end by means of a turn 320. with an outer refrigerant coil 32'. The upper end of the inner coil 32 is connected to a fitting 34 while the upper end of the outer coil 32' is connected to a fitting 36. Reference character 38 designates an inner liquid coil, the lower end of which is connected by means of a turn 38a with the lower end of an outer liquid coil 38'. The upper end of the coil 38 is connected to a fitting 40, while the upper end of the coil 38 is connected to a fitting 42. It will be noted that the turns of the inner refrigerant coil 32 alternate with respect to the turns of inner liquid coil 38, while the turns of outer refrigerant coil 32' alternate with respect to the turns of outer liquid coil 38'.

In order to assure against reverse work the space between any turn of either of the liquid coils and the closest turn of a refrigerant coil is less than the space between the turn of the liquid coil and any other turn of a liquid coil. In order that this may be so it is necessary that the radial distance between the inner and outer coils be greater than the axial distance between adjacent turns of either the two inner or the two outer coils. In this way, there is less resistance to the transfer of heat from any turn of the liquid coil to the refrigerant coil, than to another turn of the liquid coil and hence in all cases heat will be transferred to the refrigerant coil and not to another turn of the liquid coil.

As was the case in the first embodiment, the fittings at the ends of the coils are cast into the aluminium block in order to protect the coil ends against damage, both from a freeze-up and from rough handling. The thickness of the aluminium block is sufiicient to withstand the pressure resulting from a freeze-up and hence is able to prevent bursting of the liquid coils.

While we have shown two more or less specific embodiments of our invention, it is to be understood that this has been done for the purpose of illustration only and that the scope of our invention is not to be limited thereby, but is to be determined by the appended claims.

What is claimed:

1. In a heat exchange unit of the type which is used for cooling liquid with a refrigerant, a cooling tube which is adapted to have the refrigerant flow therethrough so as to produce a cooling effect in a cooling zone, a liquid tube which is adapted to have a liquid to be cooled flow therethrough and which extends substantially parallel to said cooling tube and is spaced therefrom a substantial distance throughout said cooling zone, an aluminum block structure enclosing said tubes at all points throughout said cooling zone with the tubes having end portions adjacent the extremities of said cooling zone at the surfaces of the block structure, said block structure forming a solid wall around said liquid tube throughout said cooling zone of suflicient thickness to prevent bursting of the liquid tube in the event that liquid therein freezes, and a plurality of fittings respectively surrounding and connected to said end portions of the liquid tube and reenforcing the same, each fitting having an imbedded portion which is imbedded in the block construction and having an external portion integral with and projecting outwardly from the imbedded portion beyond said cooling zone.

2. In a cooling unit for beverages or like liquids of the type which are subject to danger of being frozen because of abnormal conditions during the cooling thereof, a cooling tube extending through a cooling zone and having relatively thin walls and which is adapted to have the liquid to be cooled fiow therethrough, a block of aluminum or the like enclosing said tube substantially throughout said cooling zone with the end portions of the tube being positioned adjacent wall surfaces of the block, said metal block forming a wall of sufiicient thickness around the tube at all points to prevent injury to the tube in the event of freezing of the liquid therein, and a pair of metal reenforcing structures surrounding and connected to the respective end portions of the tube, each of said reenforcing structures forming an external portion structurally integral with the block structure and projecting from the wall surface of said block thereby to provide a reenforcement at the block surface which is sufficient to withstand stresses resulting from freezing of liquid in the tube.

3. In a cooling unit of the type which are used for beverages or like liquids which are subject to danger of being frozen because of abnormal conditions during the cooling thereof, a cooling tube which extends through a cooling zone and has relatively thin walls and which is adapted to have the liquid to be cooled flow therethrough, a block of aluminum or the like enclosing said tube substantially throughout said cooling zone with the end portions of the tube being positioned adjacent the end wall surfaces of the block, said metal block forming a wall of sufficient thickness around the tube to prevent injury to the tube in the event of freezing of the liquid therein, and a pair of metal fittings surrounding and connected to the respective end portions of the tube, each of said fittings having an external portion projecting from the wall surface of said block and reenforcing the same and an internal portion imbedded in said block thereby to provide a reenforcement at the block surface which is sufficient to withstand stresses resulting from freezing of liquid in the tube, said block being substantially bonded to the entire outer surface of the imbedded portions of the fittings and the tubing throughout said cooling zone with the bond being substantially continuous throughout.

4. In a heat exchange unit of the type which is used for cooling liquid with a refrigerant, a helical cooling tube which is formed by a plurality of evenly spaced turns and which is adapted to have the refrigerant flow therethrough so as to produce a cooling eifect in a cooling zone, a helical liquid tube which is formed by a plurality of evenly spaced turns of substantially the same diameter as the turns of said cooling tube and which is adapted to have a liquid to be cooled flow therethrough and which extends substantially parallel to said cooling tube and is spaced therefrom a substantial distance throughout said cooling zone, a cylindrical aluminum block structure having cylindrical inner and outer wall surfaces and substantially flat annular end wall surfaces, said block structure enclosing said tubes at all points throughout said cooling zone with the tubes having end portions each of which is adjacent an extremity of said cooling zone at an end wall surface of the block structure, said block structure forming a solid wall around said liquid tube throughout said cooling zone of sufficient thickness to prevent bursting of the liquid tube in the event that liquid therein, freezes, and a plurality of fittings respectively surrounding and connected to said end portions of the liquid tube and reenforcing the same, each fitting having an imbedded portion which is imbedded in the block construction and having an external portion integral with and projecting outwardly from the imbedded portion beyond said cooling zone.

CECIL BQLING.

ALEX J. TIGGES.

REFERENCES CITED The following references are of record in the 

